Many different network operators all over the world have their own laid fibers and network equipment which form multiple sub-networks. Inside their sub-networks, different network operators are solely responsible for management, maintenance, and fault location of the network equipment. However, in sequence to acquire broader coverage, network equipment of multiple different operators needs to be connected into a larger network to serve users. In this way, an end-to-end user service may be transported through sub-networks of different operators. In this case, a mechanism is required to distinguish quality conditions of sub-networks of different operators.
In order to evaluate quality conditions of sub-networks of different operators, the concept of TCM is proposed. The TCM can be used for evaluating quality conditions of sub-networks of different operators, realize sub-network monitoring, and is used for monitoring transmission quality conditions of an end-to-end service on corresponding transmission paths in different sub-networks.
The implementation principle of TCM is to define six levels of TCM overhead (OH) at an Optical Channel Data Unit (ODU) layer of an Optical Transport Network (OTN), that is, the number of TCM fields in each ODUk path may vary from 1 to 6, where k in the ODUk path represents a rate level, and k=1, 2, 3. When k is 1, it represents a rate of 2.5 Gbit/s; when k is 2, it represents a rate of 10 Gbit/s; and when k is 3, it represents a rate of 40 Gbit/s. Each leasing operator can independently accomplish real-time monitoring of an ODUk path connection state through TCM OH, and can monitor at most six levels of TCM simultaneously. In an ODUk path, OH is rewritten at a transmission source end, and extracted and monitored at a sink end, and corresponding defects are generated according to the OH. In this way, continuity monitoring, connectivity monitoring, and signal quality monitoring can be performed.
The connection of monitoring of a segment of an ODUk path through TCM OH may be nested, overlapped, and/or cascaded. FIGS. 1A and 1B are schematic views of two kinds of monitoring connection of an ODUk path. As shown in FIGS. 1A and 1B, a large sub-network exists between A1 and A2, A1 and A2 are boundaries of the sub-network, a customer service enters the sub-network from a node A1/A2, passes through the intermediate network, and leaves the sub-network from A2/A1. Meanwhile, the A1-A2 sub-network includes multiple sub-networks therein, for example, sub-networks between B1 and B2, between B3 and B4, and between C1 and C2 shown in FIG. 1A as well as sub-networks between B1 and B2 and between C1 and C2 shown in FIG. 1B. These sub-networks may be formed by the management of equipment of different equipment suppliers by the same operator or by the management of different equipment by different operators.
Currently, OH of each node in a TCM path is configured by the respective node, so that only its own OH information can be seen through the single node. When TCM OH needs to be configured, OH needs to be configured for each node first, and the user must know current OH configuration of all nodes well, so as to determine which level of TCM OH can be used to monitor a TCM segment and how to correctly configure the currently monitored TCM segment; otherwise, the original monitoring path may be destroyed due to wrong configuration. It can be seen that, no efficient TCM path management method is provided in the prior art.